Crack on Saya, how to fix :(

[huntodesu]

Hi guys, asking for your expert advice.
How can I most effectively fix this crack without risk of damaging the Saya and the Katana inside. Thanks!

 

Edited March 29 by huntodesu
typo

[Lewis B]

The bad news is that it's cracked along the grain and not along the seam. If the latter it can fixed using Sakura Nori (rice glue) which is the traditional adhesive for shirasaya. You could try using it to fill the crack and then strongly bind until dry, but I have a feeling this will not be a permanent solution especially given your climate with its high heat and humidity. I think your best bet is to find a local togishi and see if they have a few options. 

[kissakai]

Initially put a piece of leather around the crack then tightly wrap the saya and ensure the blade moves in and out the saya without touching the blade

If all OK I'd carefully glue it together with rice glue although other may have a better alternative glue. Lewis's reply came in as I was posting my post!

 

Edited March 29 by kissakai
Added line

[Bugyotsuji]

Since we can only see part of the problem I would do nothing for the time being.

You often see saya out in the marketplace that are temporarily bound with string, elastic, etc., so I would be tempted to do a temporary fix (making sure nothing is touching or rubbing as Grev says), while following Lewis's advice to find a Togi- or Saya-Shi.